1. Field of the Invention
The present invention generally relates to magnetic recording media such as for a computer disc drive, and more particularly to an exchange decoupled Cobalt/noble metal perpendicular recording medium.
2. Background of the Invention
Most modern information storage systems depend on magnetic recording due to its reliability, low cost, and high storage capacity. The primary elements of a magnetic recording system are the recording medium and the read/write head. Magnetic discs with magnetizable media are used for data storage in almost all computer systems. Various modeling and simulations have suggested that perpendicular recording (in which the medium is magnetized with a direction perpendicular to the surface of the disc, that is, in the direction of thickness thereof) is superior to conventional longitudinal recording due to various reasons, including larger optimal medium thickness, better write field efficiency, less demagnetizing fields from the stored bit pattern, etc. As the longitudinal magnetic recording technology reaches its limit in the areal density due to the lower thermal stability, perpendicular magnetic recording possesses the potential to a higher recording density. The larger perpendicular anisotropy and high remanence squareness of the Co(X)/noble metal (X=B, Cr, and etc.) multilayers suggest that these thin films are promising candidates for perpendicular magnetic recording. Doping nonmagnetic materials such as Chromium (Cr) or Boron (B) into a Cobalt (Co) layer for the Co(X)/noble metal multilayers can reduce intergranular exchange coupling and result in lower medium noise. However, the earlier studies of CoB/Pd multilayers showed that the initial CoB layers were continuous. Therefore, it could provide a source for transition media noise, resulting in lower signal-to-noise recording.
It is therefore an object of the present invention to provide a magnetic recording material for a perpendicular recording medium having improved intergranular exchange decoupling.
It is a further object of the present invention to provide a perpendicular magnetic recording medium having lower medium noise and resultant higher signal to noise recording.
It is a still further object of the present invention to provide a graded Cobalt/noble metal bilayer perpendicular recording material having alternating layers of a Cobalt alloy and a noble metal.